In the last decade, ice mass loss from Greenland contributed ~8 mm to sea level rise and Antarctica contributed ~4 mm. Since 1990, the rate of mass loss and melt have increased by ~4x in Greenland and ~6x in Antarctica. This acceleration has been primarily attributed to the warming of ocean currents that come into direct contact with the ocean-adjacent glaciers.
Fjords and ice-shelf cavities serve as connections between the open ocean and the melting glaciers. These connections deliver the heat from the deep open ocean towards the glaciers that then drives the melting at the submerged glacial face. However, the circulation within fjords and ice-shelf cavities, which controls the heat flux from the open ocean, is not well understood and is either ignored or poorly resolved in existing global climate models.
In this talk, I will present idealized numerical simulations to help better understand both the horizontal and vertical (overturning) circulation within fjords and ice-shelf cavities. Our results show that simple dynamical theories can predict the strength of the circulation and therefore be used to refine estimates of ocean-driven melting of the Greenland and Antarctic ice sheets.